title: Simple and inexpensive method for cryopreservation of fish sperm combining straw and powdered dry ice.
abstract: Here, we propose a simple and inexpensive method for fish sperm cryopreservation. Sperm samples of the loach Misgurnus anguillicaudatus (Teleostei: Cobitidae) were diluted 7-fold by an extender containing 63.5 mM NaCl, 114 mM KCl, 20 mM Tris and 10% methanol. The cryogenic straws were placed in three kinds of self-made tubes which diameter was changed by commercially available materials and then immersed into powdered dry ice for 2 min and plunged into liquid nitrogen. This procedure resulted in a cooling rate at -421.4 +/- 119.84 (control), -55.8 +/- 4.32 (tube 1), -40.2 +/- 3.43 (tube 2) and -33.3 +/- 2.09 C/min (tube 3). In the slowest cooling rate by the tube 3, total motility (72 +/- 3 %), duration (146 +/- 12 s) and hatching rates (29 +/- 04 %) were higher than those by other rates. Progressive motility (83 +/- 5 %) did not differ significantly from fresh samples.
authors.affiliation: Graduate School of Fisheries Science, Division of Marine Life Sciences, Laboratory of Aquaculture Genetics and Genomics, Hokkaido University, Hokkaido, Japan. george@fish.hokudai.ac.jp
authors.forename: George Shigueki
authors.initials: GS
authors.lastname: Yasui
authors.forename: Lenin
authors.initials: L
authors.lastname: Arias-Rodriguez
authors.forename: Takafumi
authors.initials: T
authors.lastname: Fujimoto
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Arai
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000295:instrumentation / Q000379:methods*; D003531:Cypriniformes; D004367:Dry Ice; D008297:Male; D012662:Semen Preservation / Q000379:methods*; D013081:Sperm Motility
chemical_list: D004367:Dry Ice